The present invention relates to a device for closing the pouring hole of a steel-making or metallurgical receptacle such as a pouring ladle, ingot mould or continuous-casting distributor, and more particularly to a device with a moveable plate.
A conventional pouring-hole closing device is composed essentially of a plate made of refractory material which is accommodated in a metal casing fixed under the bottom of the receptacle and of a moveable plate, likewise made of refractory material, which is mounted against the fixed plate so that it can be displaced by a translational or rotational movement in order to close the pouring orifice of the fixed plate or to position a pouring orifice with which it is provided opposite the pouring orifice of the fixed plate.
When the liquid metal is poured, the stream of metal flows out through the pouring channel of the internal nozzle, made of refractory material, of the receptacle and passes through the pouring orifices in the elements, made of refractory material, of the fixed plate and of the moveable plate of the closing device. The molten metal erodes the wall of the pouring channel and causes fairly rapid wear of the wall of the pouring orifices in the refractory elements of the fixed and moveable plates owing to the high temperature of the liquid metal. In addition, owing to the temperature a decarburisation of the binder used in the manufacture of the refractory plates occurs, which leads to a deterioration of the rubbing surfaces of the two plates, which deterioration hinders the sliding of the moveable refractory plate against the fixed refractory plate during each pouring operation.
The wear of the refractory material around the pouring orifice and the deterioration of the rubbing surfaces makes it necessary to replace the refractory plates fairly regularly after a certain number of pouring operations. These replacements are obviously costly in terms of refractory material.